Apparatus for testing the gas permeability of molded specimens



' Figure' l is a verti Figure 1 illustrates Patented Mar. 13, 1945 i 1.3

* APPARATUS FOR TESTI "ABILITY onmonnnnsrnomnns Narnia GAS'EPERME 1- I 'Application Decembcr 13,1943, Serial No. 514,139 1 U I 1713 Claims., (Cl .73 3$)' The invention-relates toapparatus for testing moldingmaterials such as molding sands;

It is the object of the inventionzto test .the gas during the casting of metal in themold. To this f In the drawing:

Figure3 is a section taken on line 33 of Molding sands and other molding materials must be sufiiciently permeable to gases and va- 'pors to permit escape of the same from the molding'chamber during the casting process. 'It is,

therefore, important "to test the, permeability of the material to determine its suitability'for forming molds. Such tests" can be made in a'cold through the material.

formed. The postB is hollowand contains a rod the bottom of'the post B. The proportions are the apparatus for forming:- a sample of the material into'a mold to be tested. This apparatuscomprises a suitable base A, a post-Bsupported thereonand which'in turn sup- .port sfa cylinder C in which the mold is to be Informing'a mold or specimen of the material to be tested, a measured quantity'of such matef pe'rmeability ofsuchmaterials and'more particularly' under conditions similar to these existing cal central-section through 1 0 an apparatus for fcrming amold of the material "to betested witha sample the'rein, and'attaching the same to'a refractory tube; f f "Fig'ure'2 is a similar view showingthe mold and tube mounted in thetesting apparatus; 1".:

such that thetube E extends upward into the space within the cylinder C while the rOd'D extends beyondftheupper end of the" tube. The

I 1 tube lC is sleeved about the upper end ot the post vB and is temporarily supported thereon by'a removable collar I which; as shown, isiof U-.

shaped' form engaging agroove I inthe post'B.

Thus, when the' collarl is removed, the tube may 'jbeptele'scoped ontothe post; as willbehereinafter 'r'ial 'is placed within the cylinder 0 and is then flt'amp'ed'by a plunger J so asto compact it to the same degree-as in forming acasting mold. The plunger is' then removed, the collar I disengaged fromthefgroove I and thecylinder is stripped from-themOId bydrawingit down on the post -;B.- This w n leave the mold K attached: to the tube E a-fter which the core D'is drawn downward' out of the'tube E for rning a chamber orlconcavity within the mold. To form a gas-tight seal be-.

tween the tube .13 and the mold, the upperend of "the tub E is coated with-'a sealingmaterial" such fa's-iscdium silicate which will cement with the sand; '-The tube Eis then disengaged from the (post B-andarefractory tube-L is sleeved thereonv to'for'm a bottom support for the mold K. The construction is then transferred to the apparatus shown in Figure 2 which comprises .a

"hollow post M having a cylindrical recess Nat its upper end; with a' tube" O extending upward through the recess andcommunicating-rwith the spacewithin thepost. Mercury is placed in the annular'channel surrounding the tube .0. At the lower end 'of'the post is a tube Pleading froma "sourceof air under-pressure and. having connected theretoa-meteringdevice Q for indicating or idecordingithe quantity of: air 'passing through 'theitube'; The metering device-may b'eanysuit- "able constructionand has inlet andoutlet .tubes Q" and Q? respectively in communication with theinterior' of thetube P.=- s'".

In" making thetest, the lower-end portions of thetubes E and L are inserted within the recess N and the mercury in said recesshwill to'rm agas-Q "tight seal'so' that anyair o'r gas passing'through the tube P intothe pcstM will be directed upward into the chamber within the mold K. However,

before the airls passed through the tube; the mold K'fis heated to a temperature substantially "the same as that' -which it would acquire in contact "with molten-metal. This may be accomplished bylowering anannular electric heating furnace R '(s'uch 'a's-shown m my former- Patent 2,279,368 issued April 14,1943) so as to surround the mold K' and heat it to the proper temperature. The furnace is then removed and'airis blownithrough "the {tube P, metering device Q; post'M, tube E, int'b thechamber withinthemold K fromwhich it passes outward through the voids between the -sa'nd particlesf "The rate of fiow is registered by the metering device Q and will thus indicate the,

gas permeabillty of the material tested 5' 1 tests may beap'plied eitherto'i green sand c mer it is necessary to treat the sodium silicate to absorb the water content thereof, which may be accomplished by treating with alcohol. On the other hand, if the specimen is first baked at a low temperature, this treatment will remove the water from the sealing material.

To avoid heating of the post M it is preferably provided with, an annular liguid circulating passages therein which is connected with any source of cooling medium. Preferably water is employed as the cooling medium and is conducted from a suitable source (not shown) through a tube T to a restricted tubegUiwith-inithc ma sage.

S. Any suitable means such as a. tube'lwi'may we employed for receiving the Water frommthe pas.-

sage S and conducting it to a suitable drainage or discharge means (not Shawn).v

What I claim as my invention is:

1. In an apparatus for testing the gas perme abilitypfi a molded specimen: having a chamber, -a-.shollowirpo.st havinguaecylindrical recessat its nner; end; atube extendin -upward" t r u thecbasezzof :the {recess and, communication with the :interionpi said-hollow post, a-second e tubeaencirclin z-rthefirst ;-t.ube. and having .its dowerlend restinssupon the b e .of Said reces -.the upper, end cf: :the'. secend zt ei s e withinithe :chamber: hf said ,specimen, a" tube sleeved zonjthecsenondatube, ,said, last mentioned tubeahavingiitsjnwer. end :restijng upon i the base of said recess ,;a-nd: having -;its upper :end forminga; supporting. zseat, ion said qspecimen, means iconnected'to: the hollow post-.forsupplfih a. gas :under rpressureithmugh the; interior of said post and-first and second tubes to the chamber of. said ispecimentorahe zrlischar ed throu h :the raids of said specimen: and-means: connect t h lamenticnedwcneans; cforzmeasurins he as. un-

plied.

I 2: Anrapparatus; -forztesting \the' gas permeability ofiarmdlded. specimen having an axially extending :chanrber; comprisin a post having a -.cylindrical'-;reaes s; atrits upp r: end and provided @below saidcupperzendvwith, a tgaszpassage a tube 'extending-.aipwardlv'through zthe-ibase of the recess fnom. said-'gasrpassage,-a second tubeencirmingrthexfirst ftubetand-havingritsloweriend'with- :int said recessytheguppen :end of the-second tube -beingysea-led z-withinrthe: chamber f aid ,specimen, airefractory tubeisleevedomthesecond tube, asaid refractoryttube having its lower-end within said recess and having its uppfir'xend forminga a supporting seat {or saidaspecimen; and -mear1srf0r supplying .a gas under. pressure :through the, gas

p s e in s id post: and said-first-and second tubes to the chamber f said ,specimemto be-zdis- :charged throughihesvoidsot said Specimen. 3.--An apparatus vforrtestingthe gas perme- .iabil-ity -;Of asmoldeda'specimenq having: a: central 1 I chamber, comprisingya post: having a- ,recess at :its :upper Lend. aand provided" below: said recess ;:with, :a: gas passages. aitube extending :upwardl-y throughithebase ofithe TEKZESSYfI OmFSQiQI gaspassage, a second tubeuericircling the first tube-land havingiits lowenend within; said recessthe upper end of the second tube-extend n :intc the-,cham- Jbehof said spec n;:meansiior supp y n a e under: pressure through the, gas :hassage' in said post and said firstandrsecondtubesto .the chamberof said 'specimento :ibe discharged through *the .voids iof saidtspecirnen; and meansconneeted to the :last mentioned rmeansviior: measuring, the

gas supplied. I v U :14. Anzanparatus: .ioricteatiilgrthe secs: R fi ability of a molded specimen having an axially extending chamber, comprising a post having a recess at its upper end and provided below said recess with a gas passage, a tube extending upwardly through the base of said recess from said gas passage, a second tube encircling the first tube and having its lower end within said recess, mercury in the recess forming a seal between thepost and first mentioned tube, the upper end of the ;second tube extending into the-chamber of said specimen, a support for said'specimen sleeved on the second tube, means for supplying a" gas under pressure through the gas passage in zsaid :postzand said-first and second tubes to the .315; ichamberxiofzgsaid specimen to be discharged through the voids of said specimen, and means connected'to'the last mentioned means for measurine-the gas supplied- 5. An apparatus for testing the gas permeability of a molded specimen having a central ,chamber; comprising a; post having a recess at its upper-. ends-and provided belowvs'aid recess twith a gas passage atube extending upwardly sthnough. the. base .of- ,the recess from said. gas ,25 massageraisecond tube ,encircling the first tube and. havingits. lower :end within said recess, the upper end .of thesecondrtube extending into the chamber of said specimen,-,a su .pport. for said specimen on the second tube,.flmean s ,for sup- .130 plying a ,gas un er pressure through the gas pas- ;sageinsaid post andsaid first ,and second .tubes .tortjhe -.chamb,er.in .saidefipeflimensto be discharged through the voids. of ,,said specimen, and, means itor ,co l-ing. the pos,t includingan, annular spas- 1,35 sage for a cooling medium within said postabout :II-hggas passage aforesaid, said ann'ularpassage being provided at substantially diametricallyopposi-t sideSt-hereof with inlet and outlet means ,for the cooling, medium. 40 6.- An apparatus. for. testing the ..gas permes-abilityeofl-lamolded. specimen having a, central vchamber, comprising a post having a recess atits ..upper endra-nd provided-below said recess with ,3 aspassagepa tube extending npwardlythrough & .the. baseeof .the recess from said gas. passa d, a second tube encirclingvthe first tube and having itslowenend within. said recess, the upper end f the second; tube, extending vinto the chamber ,,of. saidspecimen a support for said specimen .on :thesecond-tube, means for supply n a. gasunder a pressure. through -the .gaspassage in. said post- .and-said firstand second tubes to ,the chamber line-said: ,specimenstosbe. discharged through, the

voids of said specimen, means. for cooling the v postqincludin a an annularpassage for ,acodling med um w hinsaidpost-ab ut the gas passa .aforesaid, sa-id annular} passage being provided .witheinlet-and' outletrmeans for. ,the .coolingmei idium, and a restricted tube for. said cooling. me-

'60 sdium tlocatcd within, 1 said annular passage. and :COIJDBCBBd'tOwSaiG inletmeans.

- Hafimapparatus -f or. te sting the gas permeability of a moldedhspecimenhavmg.anuaxially- :extendiag. charnbenmomprhing a post having .a .re cess at itsaupper end and provided below said recess -with--a, gas :passage -a tube extendingupr'ward-ly -.th ,l1gh the base. .of .the recess ,from said I gas passage,-- a, second .tube encircling. 'the first tube and havingeitslower end within said recess,

@ mercury in saidwrecess forming Ya seal between the post andfirstmkerrtioned tube, the upper end :of; .the .second -.tube. extending. into Ithe chamber cf; said-- specimen a support; for "said specimen on saidsecond tube, aneans rfbr,supl tilying. .a' gas ,175 under pressure through the gas passage' linns'aid post and said first and second tubes to the chamber of said specimen to be discharged through the voids of said specimen, and means for cooling the post and mercury seal including an annular passage for a cooling medium within said post about the gas passage and -mercury seal aforesaid.

8. In an apparatus for testing the gas permeability of a molded specimen having a central chamber, a tube extending into the central chamber of the specimen, a refractory tube sleeved on the first mentioned tube, said refractory tube terminating short of an end of the first mentioned tube and forming a supporting seat for the specimen, means for supplying a gas under pressure through the first mentionedtube into the chamber of the specimen and out through the voids in the latter, and means for measuring the flow of gas supplied to-the chamber of the specimen.

9. In an apparatus for testing the gas permeability of a molded specimen having a central chamber, a tube having an end portion adapted of the second tube extending into the chamber of said specimen, and means for supplying a gas-under pressure through the gas passage in to be sealed within said chamber, said tube conf stituting a means by which a gasunder pressure may be introduced into the chamber of said ability of a molded specimen having a central chamber, comprising a post having a recess at its upper end and provided below said recess with a gas passage, a tube extending upwardly through the base of the recess from said gas passage, 2. second tube encircling the first tube and having its lower end within said recess, the upper end of the second tube extending into the chamber of said specimen, and means for supplying a gas under pressure through the gas passage in said post and said first and second tubes to the chamber of said specimen to be discharged through the voids of said specimen.

11. An apparatus for testing thegas permeability of a molded specimen having an axially extending chamber, comprising a post having a recess at its upper end and provided below said recess with a gas passage, a tube extending upwardly through the base of said recess from said.

said post and said first and second tubes to the chamber of said specimen to be discharged through the voids of aid specimen.

I p 12. An apparatus for testing the gas perrneability of a molded specimen having a central chamber, comprising a post having a recess at its upper end and provided below. said recess with a gas passage, a tube extending upwardly through the base of the recess from said gas passage, a second tube encirclingithe first tube and having its lower end within said recess, the upper end of the second tube extending into the chamber of said specimen, means for'supplying a gas under pressure through the gas passage in said post and said first and second tubes to the chamber in said specimen to be discharged through the voids of said specimen, and means for cooling the post including an annular passage for a cooling medium within said post about the gaspassage aforesaid, said annular passage being provided with inlet and outlet means for the cooling medium.

13. An apparatus for testing the-gas permeability of a molded specimen having an axially extending chamber, comprising a post having a recess at its upper end and provided below said recess with a gas passage, a tube extending upwardly through the base of the-recess from said gas passage, a second tube encircling the first tube and having its lower end within said recess, mercury in said recess forming a seal between the post and first mentioned tube, the upper end of the second tube extending into the chamber of said specimen, means for supplying a gas under pressure through the gas passage in said post and said first and second tubes to the chamber post and mercury seal.

HARRY w. DIETERT,

gas passage, a second tube encircling the first 

